Earth boring bit bearing system having a pitted bearing surface

ABSTRACT

The bearing surface of one relatively rotatable member of a friction bearing is grit blasted to give it a roughened surface. A reservoir containing lubricant having entrained particles of anti-galling material is connected to the friction bearing and serves as a source of anti-galling material. Particles of the anti-galling material are picked up by the roughened surface and a film of anti-galling material formed on the bearing surface.

ite tates atent 1 1 1111 3,784,264 Jackson, .11. Jan. 8, 1974 [54] EARTHBORING BIT BEARING SYSTEM 2,354,218 7/1944 Murray 184/1 E V G A PITTEDBEARING SURFACE 2,697,645 12/1954 Mitchell 303/241 [75] Inventor: G. C.Jackson, Jr., Dallas, Tex. FOREIGN PATENTS OR APPLICATIONS [73]Assignee: Dresser Industries, Inc., D ll T 874,264 8/1961 Great Britain252/26 [22] Fled: 1971 Primary ExaminerCharles J. Myhre [21] Appl. No.:120,142 Assistant ExaminerBarry Grossman Att0rneyRobert W. Mayer, ThomasP. Hubbard, Daniel Rubin, Raymond T. Majesko, William E.'John- [52][1.8. CI 308/82, 175/227, 308/241 son, JR and Eddie E. Scott [51] Int.Cl. Fl6c 33/12 [58] Field of Search 308/239, 241;

184/1 E; 29/106; 252/26; 175/227, 229 [571 ABSTRACT The bearing surfaceof one relatively rotatable mem- I References Cited ber of a frictionbearing is grit blasted to give it a UNITED STATES PATENTS roughenedsurface. A reservoir containing lubricant 3,199,878 8/1965 Cunningham6161 308 82 having entrained p r i le f anti-gaming material is2,321,203 6/1943 Henry 252 26 Connected to the friction bearing andServes as 1,913,953 6/1933 prendergrasgm 252 2 source of anti-gallingmaterial. Particles of the anti- 2,543,741 2/1951 Zweifel 252/26 gaIIingmaterial are picked up by the roughened sur- 2,839,159 6/1958 Peters252/26 face and a film of anti-galling material formed on the DCWII eta1, bearing surface 3,235,316 2/1966 Whanger 308/239 1,598,321 8/1926Sherwood 308/241 24 Claims, 5 Drawing Figures PATENTED 8 5974 SHEET 1[IF 2 INVENTOR:

G. c. JACKSON, JR

ATTORNEY PATENTED JAN 8 74 SHEET 2 BF 2 INVENTOR e. c. JACKSON, JR.

ATTORNEY I EARTH BORING BIT BEARING SYSTEM HAVING A PITTEI) BEARINGSURFACE BACKGROUND OF THE INVENTION The present invention relates to abearing system for an earth boring bit and more particularly to afriction bearing with improved performance and longer lifetimecharacteristics. The present invention is especially adapted for use onthat type of rock bit popularly known as a three cone bit; however, itsuse is not restricted thereto and the bearing system of the presentinvention can be used in other equipment wherein an improved bearingsystem is required.

A three cone rotary rock bit is adapted to be connected as the lowermember of a rotary drill string. As the drill string is rotated the bitdisintegrates theformations to form an earth borehole. The three conerotary rock bit includes three individual arms that extend angularlydownward from the main body of the bit. The lower end of each arm isshaped to form a bearing pin or journal. A cone .is mounted upon eachbearing pin (or journal) and adapted to rotate thereon. The conesinclude cutting structure on their outer surface that serves todisintegrate the formations as the bit is rotated.

A rotary rock bit must operate under very severe en vironmentalconditions and the size and geometry of the bit is restricted by theoperating characteristics. At the same time, the economics of petroleumproduction demand a longer lifetime and improved performance from thebit. in attempting to provide an improved bit, new and improvedmaterials have been developed for the cutting structure of the conesthereby providing a longer useful lifetime for the cones. This hasresulted in the bearing system being the first to fail during thedrilling operation. Consequently, a need exists for an improved bearingsystem to extend the useful lifetime of the bit.

Friction and anti-friction bearings, as well as a com bination offriction and anti-friction bearings, have been used in rotary rock bits.The anti-friction bearings employed have been typically a set of rollersand a set of balls positioned in mating raceways in the cone and bearingpin. Certain disadvantages are associated with anti-friction bearings inthat space is required to accommodate the rollers and balls and thisspace is obtained only by sacrificing bearing pin metal, cone shellthickness, or a combination of both. Friction bearings have encounteredproblems when used in rotary rock bits and have failed to provide thedesired perform: ance. it is generally necessary to have a frictionbearing length to diameter ratio of greater than two and onehalf whenoperating under severe conditions. The size limitations of a rotary rockbit make it impossible to provide this desired ratio and prior artfriction bearings used in rock bits have suffered early failure underthe severe operating conditions.

in order to obtain high penetration rates with a rotary rock bit in someformations, it is necessary to apply heavy loads on the bit and tooperate the bit at a moderate speed. With other formations, onlymoderate loads are required but the bit must be operated at relativelyhigh speeds. in addition, the rock bit operates under a highly corrosiveenvironment and is adjusted to temperature extremes. The drillingoperation may be conducted thousands of feet underground whereinelevated temperatures are encountered. The bit is continually flushed bya circulating drilling fluid to cool the bit and carry away the drillcuttings. This fluid is generally water with chemical additives tocontrol water loss or to control viscosity and/or ph. Some of thesechemicals may result in a corrosive drilling fluid. The drill cuttings,the materials encountered in the earth formations, barites added forfluid weight control, andthe chemical composition of the drilling fluidcombine to create a corrosive and abrasive drilling environment. Thebearing systems of the prior art have also experienced problems when airor other gases are used as the cooling and flushing fluid. This may bethe result of increased operating temperatures or other damagingenvironmental conditions. The bit is subjected to a wide range of fluidpressures during the drilling operation. When the bit is at the surface,it is of course only subjected to atmospheric pressure; however, whenlowered into the well bore, it will be exposed to very high fluidpressure because of the head of fluid in the well bore. ln addition, asdrilling fluid is circulated through the drill string, additionalpressures are introduced.

In view of the circumstances explained above, it can be appreciated thata bearing system for a rotary rock bit must include exceptionalperformance characteristics in a limited geometrical configuration.Since the entire drill string must be withdrawn to replace the bit whenit fails, it is highly desirable to have the bearing system operate foran extended period of time.

DESCRIPTION OF THE PRIOR ART in U. S. Pat. No. 3,595,903 to K. H. Swart,patented May 6, 1952, a three cone rock' bit is shown. The bit includesthree shanks which are assembled together to form the bit. The lower endof each shank is formed into ajournal and a generally conical toothcutter is receivable over the journal. The bearing system includesfriction-type bearings and antifriction bearings. This patent sets outsome of the problems encountered with rotary rock bits.

ln U. S. Pat. No. 3,370,895 to G. A. Cason, Jr., patented Feb. 27, 1968,another of the prior art rotary rock bits is shown. This rock bitincludes a bearing system with a lubricant reservoir containinglubricant in communication with the bearing.

In U. S. Pat. No. 3,235,316 to .l. R. Whanger, patented February 15,1966, a journal bearing for a rock bit is shown with alternating surfaceareas of wearresistant and antigalling materials. The bearing systemdisclosed in this patent includes grooves in one of the rotatablemembers and a soft metal having anti-galling characteristics positionedin the grooves.

Friction bearings of the prior art have consistently included smoothbearing surfaces on both relatively rotatable members, Individualsskilled in the art have been concerned with providing smooth bearingsurfaces and the general advancement in the art has been the developmentand combination of improved bearing materials. When anti-gallingmaterials have been provided, they have been limited to the amount ofantigalling material being present in the actual bearing structureitself and an additional source of anti-galling material has not beenincluded.

SUMMARY OF THE INVENTION The present invention provides a bearing systemhaving a long lifetime, that will support heavy loading, that canwithstand high rotational speeds, that is compatible with temperatureextremes, that may be operated under highly corrosive and abrasiveconditions, and that will withstand pressure variations. This bearingsystem includes a friction-type or journal bearing with a film ofanti-galling material that keeps the rotating parts separated andpromotes rotation. The thin film of antigalling material is maintainedby the provision of a source of anti-galling material for replacing anyportion of the film that is displaced.

In one embodiment of the present invention a three cone rotary rock bitis disclosed that will operate for an extended period of time undersevere operating conditions. One of the bearing surfaces is roughened toproduce small pits or reservoirs of a size sufficient to entrap andretain a significant amount of anti-galling material. The bearing systemincludes a lubricant reservoir filled with a lubricant containingentrained particles of anti-galling material. The lubricant and theparticles of anti-galling material enter the space between the bearingelements and a film of anti-galling material is established that insuresfree rotation.

It is therefore an object of the present invention to provide animproved bearing system with a long lifetime.

It is a further object of the present invention to provide a bearingsystem that will operate under heavy loading and high rotational speedconditions.

It is a still further object of the present invention to provide abearing system that will operate under temperature extremes.

It is a still further object of the present invention to provide abearing system for an earth boring bit that will operate under highlycorrosive and abrasive drilling conditions.

It is a still further object of the present invention to provide abearing system for an earth boring bit that will withstand pressurevariations.

It is a still further object of the present invention to provide abearing system for an earth boring bit that includes a reservoircontaining anti-galling materials.

It is a still further object of the present invention to provide abearing system for an earth boring bit including a pitted bearingsurface.

It is a still further object of the present invention to provide amethod of constructing an improved bearing system for a rotary rock bit.

The above and other objects and advantages of the present invention willbecome apparent from a consideration of the following detaileddescription of the invention when taken in conjunction with thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a three cone rotary rockbit.

FIG. 2 illustrates in vertical section one-third of a three cone rotaryrock bit incorporating a bearing system of the present invention.

FIG. 3 shows a rock bit cone with an outer bushing, pilot bushing andthrust button in place.

FIG. 4 illustrates diagrammatically and on a greatly enlarged scale themicroscopic structure of a bearing surface of the present invention.

FIG. 5 shows a journal of another embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawing andto FIG. 1 in particular, shown therein and generally designated by thereference character 10 is a three cone rotary rock bit. As illustrated,the bit 10 includes a bit body 11 including an upper threaded portion12. The threaded portion 12 allows the bit 10 to be connected to thelower end of a rotary drill string (not shown). Depending from the bitbody 11 are three substantially identical arms 13. The lower end of eachof the arms 13 is provided with an extended journal portion and thedetails of this journal portion will be discussed subsequently. Threerotary cone cutters 14 are rotatably positioned upon the three journalsextending from the arms 13. Each of the cones 14 includes cuttingstructure 15 on its outer surface adapted to disintegrate the formationsas the bit is rotated and moved downward. The cutting structure 15 isshown in the form of steel teeth; however, it is to be understood thatother cutting structure such as tungsten carbide inserts may be used asthe cutting structure 15 on the cones.

The bit 10 includes a central passageway 16 extending along the centralaxis of body 11 to allow drilling fluid to enter from the section of thedrill string immediately above and pass downward onto the cuttingstructure 15 of the cones l4 and the bottom of the hole being bored. Inuse, the drill bit 10 is connected as a lower member of a rotary drillstring and lowered into a well bore until the rotatable cones 14 engagethe bottom of the well bore. Upon engagement with the bottom of the wellbore, the drill string is rotated, rotating bit 10 therewith. Drillingfluid is forced downward through the interior passage of the rotarydrill string and continues through the central passageway 16 of bit 10passing onto the cutting structure 15 of cones 14 to the bottom of thewell bore, thence upward in the annulus between the rotary drill stringand the wall of the well bore, carrying with it the cuttings and debrisfrom the drilling operation.

As previously stated, the bearing system must insure free rotation ofcones 14 under the severe drilling environmental conditions. Theimproved bearing system of the present invention provides an earthboring bit with a long lifetime and that will withstand the conditionsencountered in drilling a deep well.

A cut-away view of one of thearms 17 of a bit incorporating the bearingsystem of the present invention is shown in FIG. 2. The bit is adaptedto be connected to a rotary drill string and operates in the mannerpreviously described. The elongated lower portion of arm 17 formsajournal 18 and a rotatable cutter 19 is mounted upon journal 18.Positioned on the exterior surface of rotatable cutter 19 is the cuttingstructure. This includes a series of tungsten carbide inserts 20. As thebit is rotated, the inserts 20 contact and disintegrate the formationsto form the earth borehole.

The bearing system of the present invention insures free rotation ofrotatable cutter 19 under the severe drilling conditions. A series ofball bearings 21 insure that rotatable cutter 19 is rotatably locked onjournal 18 and provides a portion of the bearing support. The rotatablecutter 19 is positioned upon journal 18 and the series of ball bearings21 inserted through a bore 22 extending into arm 17. After the ballbearings 21 are in place, plug 23 is inserted in bore 22 and weldedtherein by weld 24.

Journal 18 and arm 17 are also provided with a passage 25 to channellubricant from a lubricant reservoir 26 to the areas between the variousbearing surfaces. Passage 25 intersects bore 22 and plug 23 is ofreduced diameter in this area to allow the lubricant to be channeled tothe bearings. Additional passages 27, 28 and 29 allow the lubricant tobe channeled from bore 22 to the bearings. Lubricant reservoir 26 isfilled with a lubricant containing entrained particles of anti-gallingmaterial and a cap 30 locked in place on arm 17 to re tain the lubricantin reservoir 26. Cap 30 is constructed so that a passage 31 communicatesthe interior of resevoir 26 with the outside of the bit. This allowspressure equalization and prevents pressure differentials from damagingthe bearing system. A flexible diaphragm 32 serves to hold the lubricantin position and at the same time provide compensation for pressurechanges.

The lubricant containing entrained particles of antigalling materialfills reservoir 26, passage 25, bore 22, additional passages 27, 28 and29, and the spaces between the rotatable cone cutter 19 and journal 18.A-

flexible seal 33 is connected to cone cutter-19 and forms a seal betweencutter 19 and journal 18 to prevent loss of lubricant or contaminationof the lubricant from materials in the well bore. As explained above,pressure on the lubricant is equalized by cap 30 and the lubricant isnot lost or contaminated during the drilling operation. As the bit islowered into the well bore, it will be subjected to increasing fluidpressure the deeper it goes. If means had not been provided forequalizing the pressure on the lubricant, the pressure differentialacross seal 33 would be sufficient to rupture it.

Referring now to FIG. 3 a cut-away view of rotatable cone cutter 19 isshown. Positioned in the inner surface of the shell of cone cutter 19 isan outer bushing 34, a pilot bushing 35, and a thrust button 36.Bushings 34 and 35 and button 36 are locked in cone cutter 19 by forcefitting. The inner surfaces 37, 38 and 39 of the outer bushing 34, pilotbushing 35 and thrust button 34 respectively have been roughened andtherefore inelude a quantity of indentations. Specifically, the bearingsurfaces 37, 38 and 39 have approximately a 125 R.M.S. roughness. Inaddition, a thrust surface 39A on the cone 19 has been roughened toinclude a quantity of indentations giving it a roughness ofapproximately 125 R.M.S. The thrust surfaces 39 and 39A support thethrust loads and an increase .in their useful lifetime is important inextending the lifetime of the bit. The bearing surfaces of journal 18upon which cone cutter 19 rotates are relatively smooth with an R.M.S.of less than l5 and the area between the bearing surfaces contains thelubricant having entrained particles of antigalling material. Theentrained particles of anti-galling material are picked up by theroughened surfaces 37, 38, 39 and 39A and a thin film of anti-gallingmaterial established. This film keeps the bearing surfaces separated andpromotes free rotation of cutter 19. Should any of the film ofanti-galling material be lost, it will be replaced by additionalparticles of anti-galling material from the lubricant. The lubricantreservoir 26 serves as a source of anti-galling material to support freerotation of cutter 19.

The structure of one embodiment ofa bearing system of the presentinvention having been disclosed, a method of constructing a bearingsystem will now be considered with further reference to FIGS. 2 and 3.The outer bushing 34, pilot bushing 35, and thrust button 36 areconstructed of a material having the hardness and wear resistantcharacteristics of carburized and hardened steel of at least 50 rockwellC. The bushings 34 and 35 and thrust button 36 are pressed in place inthe shell of cone cutter l9 and the cutter finish ground to the desiredsize. The ball race 40 and the seal surface 41 are then masked. Theinterior of cutter 19 is grit blasted to give the bearing surfaces 37,38, 39 and 39A a roughened surface in the range of 50 to 200 R.M.S. Thismay be accomplished by directing a stream of air containing particles ofsintered tungsten carbide against the interior of cutter 19. Theparticles used to grit blast the cone shown in FIGS. 2 and 3 were of asize that would pass -l6+30 mesh screens and the air pressure was in therange of to I05 pounds. The bearing surfaces'37, 38, 39 and 39A as wellas the other bearing surfaces of the bit are prelubricated with alubricant containing particles of anti-galling material and the cutter19 is assembled upon journal 18. A series of ball bearings 21 areintroduced through bore 22 into the ball race 40. The plug 23 isinserted into bore 22 and welded into place to form weld 24. Cone cutter19 is thereby rotatably locked in place on journal 18. A lubricantcontaining entrained particles of anti-galling material is introduced tolubricant reservoir 26 and the diaphragm 32 and cap 30 locked inposition. In another embodiment of the method of the present invention,the step of prelubricating the bearing surfaces includes coating theroughened surfaces with a film or layer of anti-galling material.

The lubricant used in the embodiment of FIGS. 2 and 3 will now bedescribed in detail; however, it is to be understood that other forms ofthe lubricant may be employed as long as entrained anti-galling materialis included. The lubricant is a lithum soap grease containing puresilver particles in a ratio of 5 per cent silver particles by weight.The particles are small enough to pass a mesh screen and they aremechanically mixed with the lithum soap grease.

Referring now to FIG. 4, a microscopic study of one of the roughenedbearing surfaces containing a thin film of anti-galling material isillustrated diagrammatically. A vertical section of a bushing 42 havinga pitted surface 43 is shown on a greatly enlarged scale. A lubricant 44containing particles 45 of entrained anti-galling material coversbushing 42. The entrained particles 45 have been trapped by theindentations on the pitted surface 43 and a thin film 46 of anti-gallingmaterial has built up on the surface of bushing 42. This film ofantigalling material serves to separate the rotating members and toinsure continued free rotation of the bearing. Should any of the film 46be lost, the entrained anti-galling particles 45 in the lubricant 44 areavailable to replace the anti-galling material lost.

Referring now to FIG. 5, another embodiment of the present invention isshown. One arm 47 of a three cone earth boring bit is shown, the bitbody being constructed in a manner similar to that previously described.Ajournal 48 extends from arm 47. The surface ofjournal 48 includes aroughened bearing surface area 49. A cone (not shown) having an innerbearing surface is mounted on journal 48.'Lubricant containing entrainedparticles of antigalling material is fed from the lubricant reservoir inthe body of the earth boring bit and enters the bearing area throughopening 50. Some of the entrained particles of anti-galling material arecaptured by the roughened area 49 and a thin film of anti-gallingmaterial builds up on the bearing surface 49 of journal 48. This thinfilm of anti-galling material may be replenished by additional particlesof antigalling material from the lubricant. As the bit operates,

free rotation is insured by the bearing system of the present invention.An additional bearing surface 51 is shown that supports rotation and twoadditional bearing surfaces 52 and 53 are shown that support thrust. Itis to be understood that these bearing surfaces may be grit blasted byfollowing the method of the present invention and additional roughenedbearing surfaces thereby provided The lubricant introduced to thebearing surfaces consists of a lithum soap grease containing particlesof anti-galling materials in a ratio of percent particles ofanti-galling material and 85 percent grease. The anti-galling particlesconsist of onethird particles of copper, one-third particles of silverand one-third particles of graphite.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. An improved bearing that promotes rotation between a pair ofrelatively rotatable members, comprismg:

a rough bearing surface on one of the relatively rotatable members, saidbearing surface having a roughness of greater than 50 R.M.S.; lubricantbetween said pair of relatively rotatable members; and

anti-galling material entrained in said lubricant.

2. The bearing of claim 1 wherein said bearing surface roughness is inthe range of from 50 to 200 R.M.S.

3. The bearing of claim 1 wherein said bearing surface roughness is inthe range of from 100 to 175 R.M.S.

4. The bearing of claim 1 wherein said bearing surface roughness is inthe range of from NO to 150 R.M.S.

5. The bearing of claim 1 wherein the anti-galling material is entrainedarticulate particles of an anti-galling substance.

6. The bearing of claim 5 wherein the particles of an anti-gallingsubstance are particles of metal selected from the class represented bysilver, copper and aluminum.

7. The bearing of claim 5 wherein said particles are silver particles ina ratio of approximately 5 percent silver to approximately 95 percentlubricant by weight.

8. The bearing of claim 5 wherein said particles are copper particles ina ratio of approximately 5 percent copper to approximately 95 percentlubricant by weight.

9. The bearing of claim 5 wherein said particles are aluminum particlesin a ratio of approximately 5 percent aluminum to approximately 95percent lubricant by weight.

10. The bearing of claim 5 wherein said entrained articulate particlesare a combination of metal particles, the metals being selected theclass represented by silver, copper and aluminum.

1]. The bearing of claim 5 including means for introducing the lubricantbetween said pair of relatively rotatable members.

12. The bearing of claim 11 wherein said means for introducing thelubricant is a lubricant reservoir connected to said bearing.

13. The bearing of claim 5 wherein the particles of an anti-gallingsubstance are particles of anti-galling material selectcd from the classrepresented by silver, copper, aluminum, lead, zinc, tin, babbitt metaland graphite.

14. A bearing system, comprising:

a journal;

a rotatable member, rotatably mounted on said journal and having abearing surface with a roughness greater than 50 R.M.S.; lubricantbetween said bearing surface and said journal; and anti-galling materialentrained in said lubricant.

15. The bearing system of claim 14 wherein the antigalling material is aquantity of entrained particles of an anti-galling substance.

16. The bearing system of claim 15 wherein said bearing surfaceroughness is in the range of from 50 to 200 R.M.S.

17. The bearing system of claim 16 wherein the antigalling substance isselected from the class represented by silver, copper, aluminum, lead,zinc, tin, babbitt metal and graphite.

18. The bearing system of claim 17 including means for supplying saidlubricant to the area between said bearing surface and said journal.

19. The bearing system of claim 18 including seal means for preventingcontamination of lubricant and for preventing lubricant from escapingfrom the area between said bearing surface and said journal.

20. A bearing system for an earth boring bit, comprising:

a bit body adapted to be connected to a rotary drill string;

at least one journal connected to said bit body, with said at least onejournal including a journal bearing surface;

a rotatable cutter mounted on said at least one journal, with saidrotatable cutter including a cutter bearing surface;

a quantity of indentations on said cutter bearing surface giving saidcutter bearing surface a roughness greater than 50 R.M.S.;

a lubricant reservoir in fluid communication with the area between saidbearing surfaces; and

a lubricant in said reservoir, said lubricant containing entrainedparticles of anti-galling material.

21. The bearing system of claim 20 including seal means connected tosaid cutter for sealing the area between said journal and said cutter.

22. The bearing system of claim 21 wherein said cutter bearing surfacehas a roughness in the range of from to R.M.S.

23. The bearing system of claim 22 wherein the entrained particles ofanti-galling material are particles of material selected from the classof materials represented by silver, copper and aluminum.

24. The bearing system of claim 23 including means for equalizing thepressure in the area between the bearing surfaces and the externalpressure.

1. An improved bearing that promotes rotation between a pair ofrelatively rotatable members, comprising: a rough bearing surface on oneof the relatively rotatable members, said bearing surface having aroughness of greater than 50 R.M.S.; lubricant between said pair ofrelatively rotatable members; and anti-galling material entrained insaid lubricant.
 2. The bearing of claim 1 wherein said bearing surfaceroughness is in the range of from 50 to 200 R.M.S.
 3. The bearing ofclaim 1 wherein said bearing surface roughness is in the range of from100 to 175 R.M.S.
 4. The bearing of claim 1 wherein said bearing surfaceroughness is in the range of from 110 to 150 R.M.S.
 5. The bearing ofclaim 1 wherein the anti-gallinG material is entrained articulateparticles of an anti-galling substance.
 6. The bearing of claim 5wherein the particles of an anti-galling substance are particles ofmetal selected from the class represented by silver, copper andaluminum.
 7. The bearing of claim 5 wherein said particles are silverparticles in a ratio of approximately 5 percent silver to approximately95 percent lubricant by weight.
 8. The bearing of claim 5 wherein saidparticles are copper particles in a ratio of approximately 5 percentcopper to approximately 95 percent lubricant by weight.
 9. The bearingof claim 5 wherein said particles are aluminum particles in a ratio ofapproximately 5 percent aluminum to approximately 95 percent lubricantby weight.
 10. The bearing of claim 5 wherein said entrained articulateparticles are a combination of metal particles, the metals beingselected the class represented by silver, copper and aluminum.
 11. Thebearing of claim 5 including means for introducing the lubricant betweensaid pair of relatively rotatable members.
 12. The bearing of claim 11wherein said means for introducing the lubricant is a lubricantreservoir connected to said bearing.
 13. The bearing of claim 5 whereinthe particles of an anti-galling substance are particles of anti-gallingmaterial selected from the class represented by silver, copper,aluminum, lead, zinc, tin, babbitt metal and graphite.
 14. A bearingsystem, comprising: a journal; a rotatable member, rotatably mounted onsaid journal and having a bearing surface with a roughness greater than50 R.M.S.; lubricant between said bearing surface and said journal; andanti-galling material entrained in said lubricant.
 15. The bearingsystem of claim 14 wherein the anti-galling material is a quantity ofentrained particles of an anti-galling substance.
 16. The bearing systemof claim 15 wherein said bearing surface roughness is in the range offrom 50 to 200 R.M.S.
 17. The bearing system of claim 16 wherein theanti-galling substance is selected from the class represented by silver,copper, aluminum, lead, zinc, tin, babbitt metal and graphite.
 18. Thebearing system of claim 17 including means for supplying said lubricantto the area between said bearing surface and said journal.
 19. Thebearing system of claim 18 including seal means for preventingcontamination of lubricant and for preventing lubricant from escapingfrom the area between said bearing surface and said journal.
 20. Abearing system for an earth boring bit, comprising: a bit body adaptedto be connected to a rotary drill string; at least one journal connectedto said bit body, with said at least one journal including a journalbearing surface; a rotatable cutter mounted on said at least onejournal, with said rotatable cutter including a cutter bearing surface;a quantity of indentations on said cutter bearing surface giving saidcutter bearing surface a roughness greater than 50 R.M.S.; a lubricantreservoir in fluid communication with the area between said bearingsurfaces; and a lubricant in said reservoir, said lubricant containingentrained particles of anti-galling material.
 21. The bearing system ofclaim 20 including seal means connected to said cutter for sealing thearea between said journal and said cutter.
 22. The bearing system ofclaim 21 wherein said cutter bearing surface has a roughness in therange of from 75 to 175 R.M.S.
 23. The bearing system of claim 22wherein the entrained particles of anti-galling material are particlesof material selected from the class of materials represented by silver,copper and aluminum.
 24. The bearing system of claim 23 including meansfor equalizing the pressure in the area between the bearing surfaces andthe external pressure.